(1) Field of the Invention
The present invention relates to a technology for mounting electronic components onto a circuit board with use of ultrasonic waves.
(2) Description of Related Art
In apparatuses for mounting electronic components on circuit boards such as printed circuit boards, various methods are conventionally used for bonding the electrodes of electronic components and the electrodes of the circuit boards, among which a bonding method (hereinafter, referred to as “ultrasonic bonding”) of using ultrasonic waves is known as one of the methods that allow electronic components to be mounted in short time and at relatively low temperatures. In ultrasonic bonding, electronic components pressed against a circuit board are vibrated by ultrasonic vibrations so that the electrodes (for example, bumps are formed) of the electronic components and the electrodes of the circuit board are electrically bonded.
In the apparatus for mounting electronic components which performs such ultrasonic bonding, the bonding strength is increased to enhance the quality of mounting by heating the electrodes of the electronic components or the circuit board concurrently while applying ultrasonic vibrations to the electronic components. Such heating is usually performed by heating the circuit board from one side opposite to the side from which the electronic components are to be mounted.
Since it is not desirable to heat the entire circuit board to high temperature, a technology for heating semiconductor chips during mounting process to enhance the bonding strength is disclosed in Patent Document 1 for example. In Patent Document 1, a laser absorber provided on a bonding head is heated by applying a laser beam thereto, and the heat from the laser absorber is transferred to a semiconductor chip sucked and held by the bonding head via a heat conduction plate.    Patent Document 1: Japanese unexamined patent publication No. 2003-258037